We are coming to some text contained only in Luke. According to Luke, after the Transfiguration, Jesus exorcised a demon from a boy when Jesus' Disciples could not do so, told His Disciples that the greatest person was the least one among them (Luke 9:46-48), and said that anyone who was not against them was for them (Luke 9:49-50). From there, Luke ventures into unique territory...
...And Fire in the Sky
We begin with Luke 9:51:
As the time approached for Him to be taken up to Heaven, Jesus resolutely set out for Jerusalem. NIVThis is a key verse for synchronization of the Gospels. According to the Synoptic Gospels, this is the point where Jesus set His sights on going to Jerusalem for the first, last, and only time since He had recruited the Disciples. According to the Gospel of John, this would be the fifth and final entry into Jerusalem (the preceding four were John 2:13, John 5:1, John 7, and John 10:22-23). But, you know how it is with repeated visits, for Matthew, Mark, and Luke, all of those times probably just blended into one memory. ;-)
Anyway, with Jerusalem as the goal, Jesus sent some people to prepare a Samaritan town along their planned route for His arrival, but the townspeople rejected Jesus coming there when they heard that He had planned to continue to Jerusalem (Luke 9:52-53). The Samaritans, despite essentially sharing the same religion as the Jews, regarded their Temple on Mount Gerizim to be The Temple, as opposed to the one in Jerusalem. So we can understand why there would be some inhospitable hostility at the notion of Jesus going onto Jerusalem.
In Luke 9:54-56, we see how the news of the rejection is taken:
When the disciples James and John saw this, they asked, "Lord, do you want us to call fire down from Heaven to destroy them?" But Jesus turned and rebuked them, and they went to another village. NIVFirst, we should consider the idea of calling down fire from Heaven. This is not a new concept. God had rained down burning sulfur from Heaven on Sodom and Gomorrah (Genesis 19:24). Later, at Elijah's request, God had rained down fire from Heaven to kill over a hundred men (2 Kings 1:9-18).
So this is a Biblically consistent idea, but not a reality consistent one. It comes from a time when Heaven was thought to be the realm above the celestial ceiling that we gazed upon in the night and day. But really we are just a little blue marble, moving in the vastness of our solar system, which is poised in our gargantuan galaxy, which is situated in an incomprehensibly large universe. That makes the concept of anything raining down from a Heaven above laughable, other than meteorites, comets, and our own space junk.
As you can see, Jesus rebuked James and John for suggesting immediate divine punishment, but what exactly was that rebuke? It is not likely to have been a revelation that "Heaven" was not above them, given the Biblical view. Some people might think that this was an example of Jesus' mercy, or that Jesus' was rebuking their spirit of condemnation and retaliation. I do not think so.
Instead, Jesus' rebuke is more likely to be due to the fact that the Disciples were not following Jesus' own orders. Back when He had sent the Disciples out on their First Mission, He told them exactly what to do when a town rejected them: shake the dust off their feet as a testimony against that town (Luke 9:4-5). What was that testimony for? Luke 10:8-12 would later make clear what Matthew had stated earlier: that testimony was the ultimate condemnation for that entire town, which would be enacted at Judgement Day; resulting in a fate much worse than fire raining from Heaven. So Jesus' rebuke was probably not against the spirit of their desires, but rather a reminder that they should let God handle vengeance, and that He would do just that very soon.